Collector's Edition DLC was originally only available those who bought the retail CE version of the game. It's contains a SP training map, a weapon and a tactical weapon. The Firing Range SP map is a simple training map, where you can try all weapons in a shooting range against cardboard enemies and bullseyes. There 4 different type of challenges to complete. You can't play to other players or add any extra content to the game.
The Plasma Pulse Rifle is a new weapon to your arsenal which like other DLC weapons can't be modded. The weapon feel like a sniper, it has a scope, slow fire rate and deadly accuracy. Use only for far targets, since the fire rate is very slow and ammo is limited. The weapons can be used SP, MP and Bug Hunt modes.
The Sonic Electronic Ball Breakers are an electrical stun grenade. Can't kill an enemy, but can stun for 3-5 sec for easy kill or give you room to escape, if you surrounded with multiple enemies. But beware, it can paralyze friendlies equipment and yours too. The weapons can be used SP, MP and Bug Hunt modes.
The DLC has a small content for it's price compare to LE DLC, but if you a hardcore fan and missed the retail CE version you can pick up it for the extra weapons.